High-speed processor-based electronic systems include numerous components or subsystems some or all of which are running at different phases of a particular clock frequency (e.g., different clock domains). The communications between two components running in different clock domains is complicated by the fact that the communication of information must occur across the different clock domains, referred to as a clock domain crossing (“CDC”). As an example, a memory component of an electronic system may be running in a first clock domain while a memory controller with which the memory component exchanges information is running in a second clock domain. Transferring data between the memory controller and the memory device typically involves a CDC between the first and second clock domains.
As a result of the different clock domains of the components of the system, communications of data or other information between two components may also include a signal that indicates when the information is valid. Returning to the example above the valid signal, referred to as a strobe signal, is a timing signal that is aligned to and accompanies a data signal transmitted by the memory component (first clock domain) to the memory controller (second clock domain). The strobe signal is used by the memory controller in controlling receipt of data of the data signal.
Receipt or sampling of data under control of a strobe signal involves use of the strobe signal to generate sample clock signals that control sampling instants of a receiver associated with a data line or pin of the memory component. It often becomes necessary to gate the strobe signal so that it is only active during “read” operations when data is being received from the memory device using timing information provided by the strobe signal.
In the drawings, the same reference numbers identify identical or substantially similar elements or acts. To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the Figure number in which that element is first introduced (e.g., element 160 is first introduced and discussed with respect to FIG. 1).